The present invention relates to a method of and an arrangement for grinding of non-round workpieces with profiles, by plunge cutting on circular grinding machines with the use of a dressing roller which is kinematically coupled with a grinding wheel.
In known methods for producing or final grinding of profiles of workpieces in straight plunge cutting grinding processes, the profile shape of the workpiece and the grinding wheel peripheral surface required for it have their course in an axial direction of the grinding disc or the workpiece. The profiles of the grinding disc and the workpiece have in their respective peripheral region no deviations from a circular profile shape. However, the profile dimensions in respective portions o such workpieces or grinding wheels can have different diameters.
The German document No. DE-PS 3,029,039 shows grinding wheels which are provided on their peripheral surface with axes-parallel grooves with a depth of from 1 to maximum approximately 1,000 micrometer. These grooves serve to enable using different roughness depths for example for a coarse grinding or a fine grinding. They are arranged for this purpose with angular distances of approximately 1.degree. maximum. This solution deals therefore with microgrooves which form small webs or groove edges located directly therebetween and comparable with cutting edges in their action. For producing these grooves, a dressing roller is used which maintains a fixed speed which is dependent on the number of grooves to be produced on the grinding wheel on the one hand, and on the number of the cutting edges of the dressing roller on the other hand. For this purpose, such a dressing roll is coupled with the grinding wheel by a mechanical transmission in form-locking manner.
Such grinding wheels whose grinding surface in practice is formed as a cylindrical peripheral surface can be also used for grinding polygonal profiles on workpieces. The disadvantage of the grinding process which is used in this case is that the respective grinding machines must have two differently driven supports in the cutting or delivery adjusting direction. One support is required for producing respective movements perpendicularly t the axis of the workpiece forwardly and rearwardly, for obtaining the required profile. The movement of this support is kinematically coupled through a respective transmission with the workpiece to be ground. The second support serves for performing the required delivery movement during grinding which moves in workpiece contact only by hundredth of millimeters.
Attempts have been made to grind a non-round workpiece with a round grinding wheel which rotates with an eccentricity. Such an approach is disclosed in the U.S. Pat. No. 3,403,479. While the method and arrangement disclosed in this reference are capable of grinding the workpieces with non-round contours, they possess several disadvantages. First of all, the eccentrical rotation of the round grinding wheel creates significant imbalance forces which are detrimental to the operation of the device. Moreover, the possibilities of grinding the workpieces are very limited as to the number of possible various shapes.